Chlorosulfolipid (Danicalipin A) Membrane Structure: Hybrid Molecular Dynamics Simulation Studies

Chlorosulfolipids (CSLs) are major components of flagellar membranes in sea algae. Unlike typical biological lipids, CSLs contain hydrophilic sulfate and chloride groups in the hydrocarbon tail; this has deterred the prediction of the CSL membrane structure since 1960. In this study, we combine coarse-grained (CG) and atomistic molecular dynamics (MD) simulations to gain significant insights into the membrane structure of Danicalipin A, which is one of the typical CSLs. It is observed from the CG MD that Danicalipin A lipids form a stable monolayer membrane structure wherein the hydrocarbon moieties are sandwiched by hydrophilic sulfate and chloride groups in both the head and tail regions. On the basis of the mesoscopic structure, we built the corresponding atomistic model to investigate the integrity of the CSL monolayer membrane structure. The monolayer membrane comprising bent lipids shows high thermal stability up to 313 K. The gel-liquid crystalline phase transition is observed around 300 K.